title: The post illumination pupil response is reduced in seasonal affective disorder.
abstract: Individuals with seasonal affective disorder (SAD) may have a decreased retinal sensitivity in the non-image forming light-input pathway. We examined the post illumination pupil response (PIPR) among individuals with SAD and healthy controls to identify possible differences in the melanopsin signaling pathway. We also investigated whether melanopsin gene (OPN4) variations would predict variability in the PIPR. Fifteen SAD and 15 control participants (80% women, mean age 36.7 years, S.D.=14.5) were assessed in the fall/winter. Participants were diagnosed based on DSM-IV-TR criteria. Infrared pupillometry was used to measure pupil diameter prior to, during, and after red and blue stimuli. In response to blue light, the SAD group had a reduced PIPR and a lower PIPR percent change relative to controls. The PIPR after the blue stimulus also varied on the basis of OPN4 I394T genotype, but not OPN4 P10L genotype. These findings may indicate that individuals with SAD have a less sensitive light input pathway as measured by the PIPR, leading to differences in neurobiological and behavioral responses such as alertness, circadian photoentrainment, and melatonin release. In addition, this sensitivity may vary based on sequence variations in OPN4, although a larger sample and replication is needed.
authors.affiliation: Department of Psychology, University of Pittsburgh, 201S Bouquet St, Pittsburgh, PA 15260, USA. Electronic address: kroecklein@gmail.com.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Roecklein
authors.forename: Patricia
authors.initials: P
authors.lastname: Wong
authors.forename: Natalie
authors.initials: N
authors.lastname: Ernecoff
authors.forename: Megan
authors.initials: M
authors.lastname: Miller
authors.forename: Shannon
authors.initials: S
authors.lastname: Donofry
authors.forename: Marissa
authors.initials: M
authors.lastname: Kamarck
authors.forename: W Michael
authors.initials: WM
authors.lastname: Wood-Vasey
authors.forename: Peter
authors.initials: P
authors.lastname: Franzen
mesh_terms: D000270:Adie Syndrome / Q000209:etiology* / Q000235:genetics; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D005838:Genotype; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011569:Psychiatric Status Rating Scales; D011680:Pupil / Q000502:physiology*; D012025:Reflex, Pupillary / Q000235:genetics / Q000528:radiation effects*; D017299:Rod Opsins / Q000235:genetics; D016574:Seasonal Affective Disorder / Q000235:genetics / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D055815:Young Adult; D000099210:Melanopsin
chemical_list: D017299:Rod Opsins; D000099210:Melanopsin
keywords: Melanopsin; Pupillometry; Seasonal affective disorder